Circular dichroism and absorption spectroscopy of merocyanine dimer aggregates:: molecular properties and exciton transfer dynamics from time-dependent quantum calculations

A wave packet approach to the calculation and interpretation of circular dichroism (CD) spectra is applied to the spectroscopy of aggregates of a merocyanine dye. A combined analysis of absorption and CD spectra allows for the extraction of geometric information and excited state electronic coupling. It is shown that in the case of dimer aggregates of a chiral merocyanine dye, it is possible to infer the dynamics of an exciton transfer directly from the CD spectrum. This relation is established via the Fourier relation to a time-dependent correlation function reflecting the quantum dynamics in the dye aggregate.